Transition in Pipe Flows and Flow Resistance across Tube-Bundle Flow Straighteners.

The arrangement of tubes in a tube-bundle straightener which is used as an element in laminar flowmeters and a component in flow devices can be classified into two different patterns ; a staggered matrix and a side-by-side matrix. Fluid resistance in the straightener depends on the arrangement, the length of the tubes and Reynolds number. In this experiment, we found that a noticeable change of the pressure-loss coefficient for each matrix is caused by the transition from laminar to turbulent flow in the circular tubes and the star conduits which are elements of the tube-bundle straightener. Using conventional hot-wire measurement at the exit of the tubes, it was also observed that turbulent slag appeared at different Reynolds numbers for each circular tube and star conduit.